[Q]What is the best stock rom ?

I want to ask you, what is the best stock rom that you have used so far, from wich country or region.

I currently use South East Europe - COC2 and my operator is Orange Romania.

i want to change my current firmware because i have battery drain when using the phone and i don't know what to choose.

Can you please answer with the name of the rom that you are using and the current operator

Thank you

[Q]What ROM should I use?

Hello , as title said. Straight to the point.
My Note 4 version : Exynos N910C
Now using SweetROM, having problem that sometimes the words and icons changed to black and white, can't see words and icon.
Current version Lolipop 5.01
My note 4 SOT getting weaker, I tried some ROMS and Kernels to improve that but no helps.
Can somebody please suggest me what I should do? I'm currently planning to go back to stock Kitkat 4.4.4..
I don't think N910C have CM12.1 rom yet, I did saw the rom is still under development.

Thanks in advance. :)